1. Field of the Invention
The invention relates to a tool holder in which a tool can be clamped in place, for example a drill or a milling cutter. The invention relates in particular to an expansion chuck which is suitable for minimum quantity lubrication machining technology (MQL machining technology).
2. Description of the Related Art
In MQL machining technology, an MQL medium (oil/air mixture, e.g. aerosol) is fed to the active location of the tool (tool cutting edge). In this case, the MQL medium is almost completely used up during the machining. The quantity which is used depends on the process. It is generally up to 50 ml/process hour. The working pressure is at most 10 bar as a rule. During conventional wet machining, on the other hand, several hundreds of liters of emulsion are transferred per process hour.
The MQL machining technology is described in a new draft resolution standard DIN 69090 part 1 to 3 which is currently in preparation for adoption as a standard publication (white copy).
In order to be able to optimally utilize the advantages of MQL machining technology, losses of lubricating medium must be avoided in the entire MQL system (all the components participating in the MQL machining technology in their entirety). However, it is not easy in practice, at the transition from the machine tool to the tool holder and at the transition from the tool holder to the tool, to ensure such a tight connection that the escape of lubricating medium, which is under a pressure of up to 10 bar, is prevented. There is also the added problem that different tools are clamped in place in the tool holder.
The object of the invention is to provide a tool holder which permits loss-free passage for a lubricating medium up to the tool cutting edge and is suitable in particular for MQL machining technology with MQL medium.